1. Field of the Invention
The present invention relates generally to an electrophoresis gel processing apparatus.
2. Description of the Background Art
Gel electrophoresis is a process for distinguishing and identifying organic macromolecules. Some of the uses of gel electrophoresis are protein analysis and DNA analysis. Gel electrophoresis typically separates macromolecule components in one or two dimensions to provide a result wherein individual macromolecule components appear as bands or spots. The bands or spots may be analyzed to determine the abundance and characteristic of macromolecule components.
Humans possess a staggering number of such macromolecules whose functions and locations await discovery. In response to this challenge, a wide variety of processes and equipment systems have been developed to augment and speed up the gel electrophoresis process through large-scale automation.
Gel electrophoresis is so called because a gel medium (typically a polyacrylamide gel) is used in the process. Sample macromolecules to be analyzed are typically applied to a surface or edge of the gel. The gel is subjected to an electric field (the process of electrophoresis) and the applied macromolecules (which are generally electrically charged) move through the gel medium, yielding a physical separation of the component macromolecules.
There are different types of electrophoresis gels, with one type being a slab (or sheet), typically one to two millimeters thick and roughly the size of a sheet of paper. The gel slab is soft, rubbery, and pliable.
Slab gels may be used alone, or as the second dimension of a two-dimensional separations procedure. In the first dimension of a two-dimensional separation, a first dimension isoelectric focusing separation is performed in which proteins of a test sample are separated through a noodle-like gel strand under the influence of an electric field. As a result, the macromolecule components in the test sample are physically separated in one dimension on the basis of their electrical charges.
In the second dimension electrophoresis step of a two-dimensional electrophoresis process, the first dimension gel strand is placed on an edge of a two-dimensional gel slab (or sheet). The slab and first dimension gel strand are then subjected to electrophoresis to cause the macromolecule components to migrate through the electrophoresis gel slab. As a result of this second electrophoresis, the macromolecule components travel through the gel slab at different rates and are separated on the basis of polypeptide chain length (roughly proportional to molecular weight). The macromolecule components are therefore separated in two dimensions.
After electrophoresis, the gel slab must still be processed so that the identities, relative positions, and concentrations of macromolecule components may be determined. This may include treatment with fixatives, stains, developers, and washes. The gel may need to be submerged multiple times in such solutions, and this must be done in a controllable environment, without damage to the gel.
There remains a need in the art, therefore, for improvements in electrophoresis gel processing apparatus.